When a driver performs an operation of pressing down a brake pedal, a brake device operates, through a medium such as a brake fluid, a brake unit such as a disc brake unit to generate a braking force.
During the braking operated by the brake device described above, it is necessary to notify this to the vehicle behind or the like, and in safety standards, it is mandatory to produce a display by turning on the brake light.
Hence, in general, for example, as disclosed in JP2010-264824A, a brake light switch that is closed together with an operation of pressing down a brake pedal when the amount of operation described above becomes equal to or more than a predetermined amount of operation for generating a braking force is inserted and arranged into an electrical connection path between a power supply battery and a brake light.
In the brake light control device described above, during the braking performed by the pressing down of the brake pedal, the brake light switch operated together with this is closed to bring the electrical connection path between the power supply battery and the brake light into a conduction state. In this way, power is supplied to the brake light from the battery, and thus it is possible to notify a vehicle behind or the like of the fact that the braking is being performed by the turning on.
Incidentally, recently, for preceding vehicle following run control (ACC control) by acceleration and deceleration of the vehicle, vehicle dynamic control VDC by a left/right braking force difference, lane departure prevention control LDP and the like, a brake device has often been used that has a brake control device which can individually control a wheel braking force even by the automatic brake of a wheel regardless of the operation of the brake pedal.
In the case of the brake device described above, depending on the configuration of a brake system, a brake fluid pressure for the preceding vehicle following run control ACC, the vehicle dynamic control VDC and the lane departure prevention control LDP may cause a pressing-down stroke of the brake pedal.
In the conventional brake light control device described above, even when the brake fluid pressure for the preceding vehicle following run control ACC, the vehicle dynamic control VDC and the lane departure prevention control LDP causes the pressing-down stroke of the brake pedal, the brake light switch is closed together with this to turn on the brake light with the battery.
However, although the former preceding vehicle following run control ACC is intended to produce a vehicle speed change, the latter vehicle dynamic control VDC and lane departure prevention control LDP are not intended to decelerate the vehicle but are intended to control its direction without changing the vehicle speed while the vehicle is running. Hence, it is not necessary to provide a notification to the vehicle behind or the like, and as a matter of fact, since the unnecessary turning on of the brake light confuses the driver of the vehicle behind, no notification should be provided.
Nevertheless, as described above, the brake light is turned on when the vehicle dynamic control VDC and the lane departure prevention control LDP are performed, and thus the brake light is turned on though braking for reducing the vehicle speed is not intended, with the result that this disadvantageously confuses the driver of the vehicle behind or the like.
Conventionally, in order to solve this problem, as disclosed in JP2010-264824A, a technology is proposed in which a switching switch operated in response to left and right-wheel selection brake control by the operation of the brake control device controlling the vehicle dynamic control VDC and the lane departure prevention control LDP is inserted and arranged into the electrical connection path between the power supply battery and the brake light, and in which during the vehicle dynamic control VDC and the lane departure prevention control LDP by the brake control device, the electrical connection path between the power supply battery and the brake light is opened by the switching switch. In this way, even if the brake light switch is closed by the stroke of the brake pedal described above, the brake light is not turned on.
On the other hand, when the preceding vehicle following run control ACC is performed by the brake control device, since the vehicle speed is changed for the preceding vehicle following run, even if the pressing-down stroke of the brake pedal is not generated (even if the brake light switch operated together with this is not closed), the brake light for safety is turned on with the battery at the time of deceleration of the vehicle, and thereby it is necessary to notify such deceleration to the driver of the vehicle behind.
Hence, in JP2010-264824A, a technology is also proposed in which another switch that is closed when the brake control device performs the preceding vehicle following run control ACC is provided to be connected in parallel to the switching switch described above to satisfy the above requirement.